And in dependence on tanha arises upadana, which is usually translated as grasping or clinging.

Spiny

It is Spiny just as Dukkha is usually translated as "suffering" its actually more nuanced than that. In both cases. Upadana is posited between Tanha and Bhava ...becoming. "Grasping" or "clinging" puts the emphasis on an action, the grasping of or clinging to objects that arise in the field of consciousness. It is possible and perhaps preferable to see upadana as the a priori tendency that informs the reaction to sense objects.

The going for refuge is the door of entrance to the teachings of the Buddha.